Innovative Inverted Magnetron Experiments and Theory

Abstract

Abstract : Research at the University of Michigan has designed, simulated, fabricated, and characterized the Recirculating Planar Magnetron (RPM), a new type of High Power Microwave (HPM) device. Researchers have simulated the operation of the device in both a conventional and inverted magnetron geometry, and found the conventional geometry to be more practical. After significant computational iteration, several prototypes were fabricated and tested across a wide parameter space encompassing -250 to -300 kV, 0.18-0.3 T, and pulselengths of 200-500 ns. To improve device operation, multiple cathode designs were simulated and tested, varying both geometry and material properties. The RPM demonstrated peak instantaneous electronic efficiencies as high as 32%, and peak powers of up to 150 MW at 1 GHz. A patent was filed and granted on this RPM device during this grant. A 1.89 GHz variant, the RPM-CACE, has been designed and optimized in collaboration with Air Force Research Lab. Its unique coupler design, the Coaxial All-Cavity Extractor (CACE), provides an efficient, broadband method of power extraction where axial power extraction is desired. In simulation, the RPM-CACE was up to 70% efficient, producing peak microwave powers of 420 MW.